Debonding of Thin Bonded Rubberised Fibre-Reinforced Cement-Based Repairs under Monotonic Loading: Experimental and Numerical Investigation

Abstract

In this study, the durability of cement-based repairs was observed, especially at the interface of debonding initiation and propagation between the substrate–overlay of thin-bonded cement-based material, using monotonic tests experimentally and numerically. Overlay or repair material (OM) is a cement-based mortar with the addition of metallic fibres (30 kg/m3) and rubber particles (30% as a replacement for sand), while the substrate is a plain mortar without any addition, known as control. Direct tension tests were conducted on OM in order to obtain the relationship between residual stress-crack openings (σ-w law). Similarly, tensile tests were conducted on the substrate–overlay interface to draw the relationship between residual stress and opening of the substrate–overlay interface. Three-point monotonic bending tests were performed on the composite beam of the substrate–overlay in order to observe the structural response of the repaired beam. The digital image correlation (DIC) method was utilized to examine the debonding propagation along the interface. Based on the different parameters obtained through the above-mentioned experiments, a three-point bending monotonic test was modelled through finite elements using a software package developed in France called CAST3M. Structural behaviour of repaired beams observed by experimental results and that analysed by numerical simulation are in coherence. It is concluded from the results that the hybrid use of fibres and rubber particles in repaired material provides a synergetic effect by improving its strain capacity, restricting crack openings by the transfer of stress from the crack. This enhances the durability of repair by controlling propagation of the interface debonding.

Mechanical Performance of Amorphous Metallic Fiber-Reinforced and Rubberized Thin Bonded Cement-Based Overlays

“…The increase in the deflection of the composite prisms was due to the bridging action provided by the steel fibers against the crack opening. Similarly, an increase in peak load and corresponding deflection was observed in recent study conducted on rubberized fiberreinforced overlays [44]. The curves show that peak load as well as the corresponding deflection increased as compared to the control mortar with fiber reinforcement of repair material.…”

“…The increase in the deflection of the composite prisms was due to the bridging action provided by the steel fibers against the crack opening. Similarly, an increase in peak load and corresponding deflection was observed in recent study conducted on rubberized fiberreinforced overlays [44].…”

“…It was observed that steel fibers had the capacity to control debonding by restraining the opening of cracks. Debonding initiation and its propagation along overlay-substrate interface of thin bonded cement-based material under bending loading were studied by Gillani et al [44]. They found that strain capacity improved for the composite beams repaired with the material incorporating both rubber aggregates and metallic fibers.…”

Influence of Different Types of Fillers on the Performance of PMMA-Based Low-Temperature Rapid Repair Mortar

“…Ordinary silicate cement mortar is prone to brittle fracture and high shrinkage, which is not conducive to the compatibility between the repair mortar and the concrete pavement. In order to solve this problem, some scholars added various types of fibers or used early-strength or fast-hardening special cement for modification and optimization [ 6 , 7 , 8 , 9 , 10 , 11 , 12 , 13 ], which greatly improved the toughness of the repair mortar and shortened the maintenance time. Another part of scholars choosed to use epoxy resin, polyurethane, methyl methacrylate and other polymers as repair materials to replace cement mortar [ 14 , 15 , 16 , 17 ].…”